This article investigates physical layer security (PLS) in reconfigurable intelligent surface (RIS)-assisted multiple-input multiple-output multiple-antenna-eavesdropper (MIMOME) channels. Existing researches ignore the problem that secrecy rate can not be calculated if the eavesdropper's instantaneous channel state information (CSI) is unknown. Furthermore, without the secrecy rate expression, beamforming and phase shifter optimization with the purpose of PLS enhancement is not available. To address these problems, we first give the expression of secrecy outage probability for any beamforming vector and phase shifter matrix as the RIS-assisted PLS metric, which is measured based on the eavesdropper's statistical CSI. Then, with the aid of the expression, we formulate the minimization problem of secrecy outage probability that is solved via alternately optimizing beamforming vectors and phase shift matrices. In the case of single-antenna transmitter or single-antenna legitimate receiver, the proposed alternating optimization (AO) scheme can be simplified to reduce computational complexity. Finally, it is demonstrated that the secrecy outage probability is significantly reduced with the proposed methods compared to current RIS-assisted PLS systems.
翻译:本条调查了可重新配置智能表面(RIS)协助的多输出多输出输出多亚ANTAN-Eavestop(MIMOME)通道中的物理层安全(PLS) 。 现有的研究忽略了一个问题, 即如果窃听器的瞬间频道状态信息( CSI)未知, 便无法计算保密率。 此外, 没有保密率表达、 光成形和 级转移器优化, 目的是加强 PLS 。 为了解决这些问题, 我们首先将任何正在成型的矢量和级转移器矩阵的保密性超出概率表达作为以静脉冲驱动器( MIMOME) 的统计 CIS 衡量标准。 然后, 在表达的帮助下, 我们提出了保密性超出概率最小化的问题, 这个问题通过替代优化波形矢量矢量和级转移矩阵来解决。 在单亚硝纳发射器或单安诺纳合法接收器的情况下, 拟议的交替优化( AO) 计划可以简化, 以减少计算复杂性。 最后, 将 与提议的保密性保证系统 大大降低与当前计算复杂性相比, 。 。 。 将 将 。